To examine the relationship between fetal gender and postpartum depression, we conducted a cohort study in Changsha, Hunan, China between September 2004 and January 2005. Women aged 18-40 years with their first live birth of a singleton infant who came to hospital for postpartum examination at 6 weeks after childbirth were invited to participate. Women with known psychiatric disorders or a history of psychiatric disorders were excluded. Data on demographic and clinical information were collected. Postpartum depression was assessed by the Chinese version of the Edinburgh Postnatal Depression Scale. Fifty-two women (17.3%) were found to have postpartum depression. The rate of postpartum depression in women who gave birth to a female infant was 24.6% while the rate in those women who gave birth to a male infant was 12.2%. The relative risk for postpartum depression of women who gave birth to a female infant as compared with those who gave birth to a male was 2.89, after adjusting for potential confounding by maternal age, education level, family income, living condition, gravidity, number of prenatal care visits, and mode of delivery. We conclude that the risk of postpartum depression is increased in Chinese women who give birth to a female infant as compared to those who gave birth to a male infant. We speculate that this is associated with the negative reactions of family members towards the birth of a female baby.